1. Field of the Invention
This invention relates to fluidic oscillators. More specifically, the invention is a fluidic oscillator array that synchronizes the oscillations of the array's output jets.
2. Description of the Related Art
In the 1900s, fluidic oscillators were developed for use as logical function operators. More recently, fluidic oscillators have been proposed for use as active flow control devices where an oscillator's jet output is used to control a fluid flow (e.g., gas or liquid). FIGS. 1A-1C schematically illustrate the basic operating principles of a fluidic oscillator. Briefly, fluid flow 100 enters a fluidic oscillator 10 at its input 10A and attaches to either sidewall 12 or 14 (e.g., right sidewall 14 in the illustrated example) due to the Coanda effect as shown in FIG. 1A. A backflow 102 develops in a right hand side feedback loop 18. Backflow 102 causes fluid flow 100 to detach from right sidewall 14 (FIG. 1B) and attach to left sidewall 12 (FIG. 1C). When fluid flow 100 attaches to left sidewall 12, a backflow 104 develops in left hand side feedback loop 16 which will force fluid flow 100 to switch back to its initial state shown in FIG. 1A. As a result of this activity, fluid flow 100 oscillates/sweeps back and forth at the output 10B of oscillator 10.
In order to achieve relatively large scale active flow control, a number of fluidic oscillators (such as the one described above) can be arranged such that their output jets are arrayed in an area requiring flow control. One drawback associated with arrays of fluidic oscillators is that each fluidic oscillator output jet will oscillate independently of other output jets. Therefore, the resulting array output tends to be random in nature. While this result can be preferable for mixing applications, it does not provide the result predictability needed for efficient active flow control.